2-azabicyclo(2,2,2)octane-3-carboxylic acid derivatives for the treatment of disorders of the cerebral circulation

ABSTRACT

Use of 2-azabicyclo[2.2.2]octane-3-carboxylic acid derivatives and their salts for the production of medicinal products intended for the treatment of arteritis and more especially arteritis of the lower limbs, disorders of the cerebral circulation and more especially disorders of cerebral senescence and migraine, and disorders of vision such as retinal disorders of vascular origin, diabetic retinopathy, chorioretinal atrophy and chorioretinal degeneration.

This is a divisional of application Ser. No. 396,864, filed Aug. 22,1989, now U.S. Pat. No. 5,025,425, issued June 4, 1991.

The present invention relates to the use of 2azabicyclo[2.2.2]octane-3-carboxylic acid derivatives for the treatment ofvascular diseases.

More specifically, the invention relates to the use, for the treatmentof diseases resulting from impairment of the vascular wall or ofdisorders of the microcirculation, of derivatives of general formula(I): ##STR1## in which A denotes a vinylene or dimethylene radical,

q is 0 or 1,

R denotes a lower alkyl radical which can bear an amino group,

X denotes --S-- and R₁ denotes H, or alternatively X denotes --NH-- and

R₁ denotes a hydrogen atom or a radical of formula: ##STR2## R₂ denotesa hydroxyl or a lower alkoxy group, R₃ denotes a hydrogen atom, a linearor branched alkyl, cycloalkyl or phenylalkyl radical having not morethan 8 carbon atoms in all, or a radical of formula: ##STR3## in which:R₄ is H or a lower alkyl or (C₃ to C₆)cycloalkyl radical,

R₅ is H or a (C₃ to C₆)cycloalkyl or (lower alkoxy)-carbonyl radical,and

p is 1 or 2,

on the understanding that lower alkyl or alkoxy radical denotes groupshaving from 1 to 4 carbon atoms, as well as their addition saltsobtained with a therapeutically compatible inorganic or organic base orwith a therapeutically compatible inorganic or organic acid when Xdenotes NH.

As a base capable of salifying the compounds of formula (I), sodiumhydroxide, potassium hydroxide, calcium hydroxide or aluminum hydroxide,alkali metal or alkaline-earth metal carbonates or organic bases such astriethylamine, benzylamine, diethanolamine, tert-butyl-amine,dicyclohexylamine, arginine, and the like, may be used.

Among acids which can be added to the compounds of formula (I) to obtainan addition salt, hydrochloric, sulfuric, phosphoric, tartaric, malic,maleic, fumaric, oxalic, methanesulfonic, ethanesulfonic, camphoric andcitric acids, and the like, may be mentioned without implied limitation.

The compounds of formula (I) contain at least two asymmetric carbonatoms. The use according to the invention can relate to the differentisomers of the derivatives of formula (I), isolated or even as amixture. However, the use according to the invention relatespreferentially to the derivatives of formula (I) in which the asymmetriccarbon atoms have the S configuration.

The compounds of formula (I) which are preferentially usable accordingto the invention are those for which:

A denotes a dimethylene group,

q is 0,

R denotes a methyl or 4-aminobutyl group,

X denotes NH, and

R₁ denotes a radical of formula: ##STR4## R₂ possessing the definitionstated above, R₆ denoting a methyl, ethyl or phenyl group, as well astheir addition salts.

Among the latter, that for which R₂ denotes ethoxy and R₆ is a phenylradical, and R denotes a methyl group, is preferred. The compound inquestion is(S,S,S)-2-{2-[3-phenyl-1-(ethoxycarbonyl)propylamino]propionyl}-3-carboxy-2-azabicyclo[2.2.2]octane.

The compounds of the formula (I) are described in European Patent0,051,020, as well as in European Patent Application 0,105,102, as beingusable in the treatment of arterial hypertension at dosages of between 1and 200 mg.

The Applicant has now discovered that the products of formula (I)possess advantageous properties, applicable for the treatment ofdiseases due to an impairment of the vascular wall, as well as for thetreatment of diseases resulting from disorders of the microcirculation,and at doses not giving rise to antihypertensive activity.

Among the conditions capable of being treated by the medicinal productsobtained according to the invention, arteritis, arteritis of the lowerlimbs, and also disorders of the cerebral circulation and especiallydisorders of cerebral senescence and migraine, and disorders of visionsuch as retinal disorders of vascular origin, diabetic retinopathy,chorioretinal atrophy and chorioretinal degeneration should bementioned.

The medicinal products intended for the treatment of diseases resultingfrom impairment of the vascular wall as well as for disorders of themicrocirculation, obtained using, according to the invention, thecompounds of formula (I) or their pharmaceutically acceptable salts,will be presented in pharmaceutical dosage forms suitable for oral,parenteral and, in particular, intravenous, per- or transcutaneous,nasal, rectal, perlingual, ocular or respiratory administration, and inparticular injectable preparations, aerosols, eye or nose drops,tablets, sublingual tablets, sublingual preparations, hard gelatincapsules, capsules, pills, suppositories, creams, ointments, skin gels,and the like.

The dosage varies according to the patient's age and weight, theadministration route and the nature of the therapeutic indication and ofassociated treatments, and ranges from 0.001 mg to 10 mg per dose or perapplication.

The examples which follow illustrate the invention and in no way limitthe latter.

EXAMPLE 1 ACTIVITY OF THE PRODUCTS OF FORMULA (I) AT NON-HYPOTENSIVEDOSES ON PLASMA CONVERTING ENZYME

The use of a derivative of formula (I) --having converting enzymeinhibitory properties --in the treatment of diseases resulting fromimpairment of the vascular wall as well as for disorders of themicrocirculation, presupposes that this product is active with respectto converting enzyme at non-hypotensive doses.

A study was hence carried out on Sprague-Dawley rats weighing from 80 to100 grams. This group of animals received a product of formula (I) inthe drinking water on the basis of 0.1 mg.kg ; another group of animalswas not treated. After 7 days of treatment, the rats are anesthetizedwith 50 mg kg of pentobarbital sodium. A catheter is introduced into thecarotid for the collection of two samples, one in a dry tube for assayof the converting enzyme activity, the other on EDTA for the assay ofangiotensin I. After collection, the samples are immediately centrifugedat 4° C. and 3,000 rpm for 10 minutes. The supernatants are withdrawnand frozen at -80° C. while awaiting assay. The outcome of the study isthat 7 days, oral administration of the product of formula (I) at 0.1mg.kg⁻¹ /day led to a 52 % inhibition of the circulating enzyme. Thisresult demonstrates that the products of formula (I) act on convertingenzyme at non-hypotensive doses.

EXAMPLE 2 DEMONSTRATION OF THE EXISTENCE INSIDE THE VASCULAR WALL OF ARENIN-ANGIO-TENSION SYSTEM SENSITIVE TO THE PRODUCTS OF FORMULA (I)

The experiment was carried out on the femoral and internal saphenousarteries and the saphenous vein of pigs. Minipigs (Charles-River) wereanesthetized by an intramuscular injection of 1.5 mg kg⁻¹ of Stresniland an intraperitoneal injection of pentobarbital sodium (40 mg kg⁻¹),and drained of their blood.

After being collected, the blood vessels were cleared of adherentconnective tissue and cut into segments approximately 4 mm long, andwere stored in modified Krebs-Ringer bicarbonate medium.

The isometric tension was measured with a tensiometer indicator (GouldUC₂) connected to a recorder (Gould). The vascular segments were broughtto the optimal point of their length/tension ratio by repeatedstimulations with 40 mM KCl.

The vessel segments were left to stand for the purpose of equilibrationof the preparation for 45 minutes before the beginning of eachexperiment. The vascular endothelium was removed from some samples bygently rubbing the surface of the intima using a small forceps.

It was shown that angiotensinogen, angiotensin I (1·10⁻¹⁰, 3·10⁻⁷ M) andangiotensin II (10⁻¹⁰, 10⁻⁷ M) induced contractions of the femoralarteries. These contractions are dependent on the presence of theendothelium for angiotensinogen and angiotensin I; a completerenin-angiotensin system is hence present in the vascular wall.

It was also shown that products of formula (I) act essentially on theconverting enzymes present in the vascular endothelium, therebydemonstrating that the products of formula (I) are capable of being usedin the production of medicinal products intended for the treatment ofdisorders affecting this vascular wall.

EXAMPLE 3 ACTIVITY OF THE PRODUCTS OF FORMULA (I) WITH RESPECT TO ANISCHEMIC MICROCIRCULATION

The experimental study was carried out on the cremaster muscles of malerats (Sprague-Dawley) after ligation of the common iliac artery.

The muscles were placed in a transparent chamber and perfused withbicarbonate buffer solution equilibrated with a 5:95 % CO₂ /N₂ gaseousmixture. The velocity of the red cells and the diameter of the first orsecond order arterioles irrigating the cremaster were measured, and thearteriolar blood flow was calculated. Identical data were obtained forfour types of venules.

The same types of measurement were performed simultaneously:

on the cremaster perfused normally,

on the ligated cremaster, that is to say the cremaster rendered ischemic2, 7, 14 and 21 days after ligation.

Two groups of animals were studied:

an untreated control group,

a group treated orally with a product of formula (I), on the basis of0.1 mg.kg⁻¹ per day.

No difference was observed in the velocity of the red cells or in thediameter of the vessels in the normally irrigated cremaster muscles inthe treated animals compared with the controls.

In contrast, as regards the cremaster muscle rendered ischemic, the meandiameter of the arterioles was improved in the treated animals comparedwith the controls. The velocity of the red cells was normalized by atreatment for 21 days.

In fact, in the treated animals, the velocity of the red cells and theblood flow rate measured 7 days after ligation show no significantdifference from the values obtained in the cremaster not renderedischemic. These results are obtained without modification of thearterial blood pressure.

These results indicate that chronic treatment with a compound of formula(I) improves the microcirculation and blood irrigation of regionsrendered ischemic.

EXAMPLE 4 ACTIVITY OF THE COMPOUNDS OF FORMULA (I) ON THE TRANSMEMBRANEMOVEMENTS OF MACROMOLECULES AT MICROVASCULAR LEVEL IN MUSCLE RENDEREDISCHEMIC

The in vivo effects of the products of formula (I) on the transvascularmovements of macromolecules induced by ischemia were studied.

The preparation involved rat cremaster muscle placed in a transparentchamber and perfused with bicarbonate buffer solution equilibrated witha 5 % : 95 % CO₂ /N₂ gaseous mixture so as to obtain a pH of 7.40.

Bovine serum albumin (fraction IV) labeled with fluoresceinisothiocyanate (FITC-BSA) was injected as a macromolecular tracer (15mg.kg⁻¹). Ischemia was produced for one hour with a clamp placed on themain artery of the cremaster muscle.

The clearance of FITC-BSA was calculated by the ratio of theextravasation per unit tissue weight to the plasma FITC-BSAconcentration, this result being expressed as a percentage of the meanvalue obtained during a prior 20-minute control period.

The animals treated orally for 3 days with 1 mg.kg⁻¹ per day of aproduct of formula (I) show a higher macromolecular extravasation underthe effect of bradykinin than that found in the control animals. Theseresults demonstrate the inhibitory effect of a product of formula (I) onthe angiotensin-converting enzyme present in the muscularmicrocirculatory system.

A treatment with a compound of formula (I) significantly reduces theincrease in microvascular permeability observed in vivo as a result ofone hour of total ischemia.

EXAMPLE 5 ACTIVITY OF THE COMPOUNDS OF FORMULA (I) WITH RESPECT TO THEELASTIC PROPERTIES OF RAT AORTA

The impairment of the elastic properties of rat aorta was studied inthree groups of Goldblatt rats.

Hypertensive rats were treated for five weeks with a product of formula(I) on the basis of 0.1 mg.kg⁻¹ and 0.01 mg.kg⁻¹ ; their aortae werestudied after five weeks and compared with the aortae of rats which hadnot received any treatment.

Aortic fragments were suspended in organ chambers filled with modifiedKrebs Ringer bicarbonate solution. These fragments were treated withpapaverine (10⁻⁴ M) and sodium nitroprusside (10 ⁻⁴ M) to suppress anyinterference due to the active tension developed by the smooth muscle.Aortic fragments from hypertensive rats developed a higher tension thanthat of the aortic fragments from normotensive rats subjected toidentical stretching.

The treatment of sham-operated and normotensive rats with 0.1 mg.kg⁻¹per day of the product of formula (I) did not give rise to significantdifferences from the controls, which were also sham-operated. The aorticfragments of hypertensive rats treated with 0.01 mg.kg⁻¹ per day ofproduct of formula (I) developed a lower tension than that of theuntreated animals.

The results of a test of this kind confirm the possibilities of usingmedicinal products obtained from compounds of formula (I) in disordersof the vascular wall.

EXAMPLE 6 EFFECTS OF A CHRONIC ADMINISTRATION OF NON-HYPOTENSIVE DOSESOF COMPOUNDS OF FORMULA (I) IN HYPERTENSIVE RATS

This study, carried out in a large number of rats, shows, in the firstplace, that the onset of hypertension resulting from the installation ofa clip on the renal artery gives rise to a parallel and significantincrease in the weight of the aorta (Goldblatt rat) (+21 %).

The compounds of formula (I), administered at a dose of 0.1 mg.kg⁻¹ perday for 5 weeks in sham-operated rats, do not modify the blood pressure,but give rise to a significant decrease in the weight of the aorta (-14%) of the treated rats in comparison with rats treated with placebo.

This test shows the important part played by the derivatives of formula(I), administered chronically, with respect of the properties of thevascular wall.

EXAMPLE 7 PHARMACEUTICAL COMPOSITON

Preparation formula for 1,000 tablets containing a 0.3 mg dose of activeprinciple.

    ______________________________________                                        (S)-2-{(S)-2-[(S)-1-Ethoxycarbonyl-3-phenylpropyl-                                                       300    mg                                          amino]-1-oxopropyl}-3-carboxy-2-azabicyclo[2.2.2]-                            octane                                                                        Hydroxypropylcellulose     2      g                                           Wheat starch               10     g                                           Lactose                    100    g                                           Magnesium stearate         3      g                                           Talc                       3      g                                           ______________________________________                                    

I claim:
 1. A method for the improvement of the cerebral circulation,ina patient in need of the same, comprising the step of administering tosaid patient an amount of a 2-azabicyclo-[2.2.2]octane compound ofFormula I; ##STR5## in which A denotes dimethylene,q is 0, R denoteslower-alkyl (C₁ -C₄) which can bear an amino group, X denotes --NH--,and R₁ denotes ##STR6## wherein R₂ denotes hydroxyl or (C₁ -C₄)lower-alkoxy, R₃ denotes (C₁ -C₄) alkyl, or phenyl (C₁ -C₄) alkyl, or apharmaceutically-acceptacle salt thereof with athereapetically-compatible inorganic or organic base or with atherapeutically-compatible inorganic or organic acid but essentiallydevoid of antihypertensive effect which is effective for said purpose.2. A method of claim 1 wherein the asymmetric carbon atoms in thecompound of Formula I have the S configuration.
 3. A method of claim 1wherein, in the compound of Formula I, R=methyl and R₃ =2-phenyl-ethyl.4. A method of claim 1 wherein the compound of Formula I is(S,S,S)-2-{2-[3-phenyl-1-(ethoxycarbonyl)propylamino]-propionyl}--3-carboxy-2-azabicyclo[2.2.2]octaneor a salt thereof with a pharmaceutically-acceptable inorganic ororganic base or a pharmaceutcially-acceptable inorganic or organic acid.5. A method of claim 3 wherein the daily dosage is not more than about0.1 mg. kg³¹ 1 /day.
 6. A method of claim 4 wherein the daily dosage isnot more than about 0.1 mg.kg⁻¹ /day.